Communications networks, including without limitation wide area networks (“WANs”), local area networks (“LANs”), and storage area networks (“SANs”), may be implemented as a set of interconnected switches that connect a variety of network-connected nodes to communicate data, share hardware resources, and/or control packets among the nodes and switches. For example, a SAN may be implemented as a high-speed, special purpose network that interconnects different kinds of data storage devices with associated data servers on behalf of a large network of users. Typically, a SAN includes high performance switches as part of an overall network of computing resources for an enterprise. A SAN may be clustered in close geographical proximity to other computing resources, such as mainframe computers, but may also extend to remote locations, such as other enterprise sites, for backup and archival storage using wide area network carrier technologies. Data storage devices and data servers may be collectively referred to as “nodes” connected to the network.
A SAN is often used if a particular application requires SAN capabilities, so a small, isolated SAN is developed for that particular application. In many cases, a different department or application within an organization will need a SAN and will have a SAN developed for that department or application, as well. The development of multiple isolated SANs, however, may waste valuable resources because the SANs do not share any resources. Thus, in some situations it would be desirable to have connectivity between these isolated SANs to provide overall management and to provide more efficient and scalable use of various resources while still maintaining separate fabrics or networks.
Fibre Channel networking is typically used in SANs although other communications technologies may also be employed, including Ethernet and IP-based storage networking standards (e.g., iSCSI, FCIP (Fibre Channel over IP), etc.). As used herein, the term “Fibre Channel” refers to the Fibre Channel (FC) family of standards (developed by the American National Standards Institute (ANSI)) and other related and draft standards. In general, Fibre Channel defines a transmission medium based on a high speed communications interface for the transfer of large amounts of data via connections between varieties of hardware devices. Other networking protocols may additionally or alternatively be employed, such as raw Ethernet, TCP/IP, USP, etc.
As a Fibre Channel fabric (FCF) develops and grows in size, the stability of the Fibre Channel fabric may be reduced when an event occurs. In addition, when a Fibre Channel fabric is formed of various types of devices, it becomes increasingly difficult to maintain the scalability and performance of the fabric.
Logical networks, such as Logical Storage Area Networks (LSANs), can be created to share resources between two or more communications networks, such as FCFs. These logical networks are typically administered by zoning, in which a logical zone defining the devices to be shared is created in each isolated communication network, and a network switch attached to the two or more isolated networks “listens” for the creation of “matching” zones on the attached networks. The creation and administration of logical networks spanning multiple isolated communications networks, however, is resource intensive and may compromise scalability, performance, and security of the logical network.
Additionally, hardware and protocol requirements make some devices in large communications networks sensitive to timeout and retry during discovery processes.